A Measuring Method of the Displacement along a Circle Based on the Sequential-Three-Point Method. A Study of the Measuring Principle and Error.

A sequential-point method is often used for straightness measurement of machined parts. In a previous paper, we proposed the principles of the measuring method of roundness and flatness based on the sequential-three-point method. In this paper, we discuss the measuring error of the displacement along a circle, which forms the basis for roundness and flatness measurement. This paper shows the experimental results and computer simulation to investigate the theoretical results. In summary:1) A displacement error caused by output error of the sensor is estimated by computer simulation and 2) the error of the displacement measured along a circle is much smaller than the error of straightness measurement. Both errors are based on the sequential-three-point method.